DebuggingProgramCrash
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This document describes how to install debug packages on Ubuntu, which will aid in providing information for bugs.
Feisty Fawn 7.04, Gutsy Gibbon 7.10 and Hardy Heron 8.04
Use this section only if you are using Ubuntu Feisty 7.04, Gutsy 7.10 or Hardy 8.04. See the following section if you are using a prior version.
1. Add the following lines to /etc/apt/sources.list: (of course, replace hardy with feisty if you're using 7.04 or gutsy for 7.10)
{{{deb http://ddebs.ubuntu.com hardy main universe
deb http://ddebs.ubuntu.com hardy-updates main universe deb http://ddebs.ubuntu.com hardy-proposed main universe deb http://ddebs.ubuntu.com hardy-security main universe }}}
You may also add these lines using the Synaptic Package Manager:
a. Choose Synaptic via the System > Administration menu.
b. Choose Software Sources via the Settings menu, and click on the Third-Party Software tab.
c. Click the Add button and enter each deb ... line as above one by one and click the Add Source button (you will have to add these lines one at a time).
d. Click the Reload button once you are done adding all the deb lines.
2. Then run
sudo apt-get update
to update your package list.
3. The debug symbol packages have the '-dbgsym' suffix attached, so to install the debug symbols for the package 'yelp', you run:
dpkg -l yelp
Note the version number installed, e.g. 2.22.1-0ubuntu2.8.04.1, then run:
sudo apt-get install yelp-dbgsym=2.22.1-0ubuntu2.8.04.1
Alternatively, main Ubuntu repositories could contain '-dbg' debug symbol packages. Those are equivalent to '-dbgsym'. You could use the one you want, but not both.
- Now you make a ["Backtrace"].
- You can also run ["Valgrind"], if the program crashes with a "Segmentation fault" or "Bus error".
- Optionally, you may be asked to produce an ["Strace"].
You can also provide this file : ~/.xsession-errors
References
Prior Ubuntu versions
Use this section if you are using an Ubuntu version prior to Feisty 7.04.
Check if the package has a debugging version available. In general, debugging packages will be named with a -dbg suffix
- If not, you can generally* build one this way:
Something to keep in mind: if you would like to create a build you're going to need to have the relevant deb-src lines in your /etc/apt/sources.list
- Install the development scripts:
sudo apt-get install devscripts fakeroot
- Find out to which package your program belongs to:
dpkg --search <program>
- Install the build-time dependencies for the package:
sudo apt-get build-dep <package>
- Build .debs for debugging:
export DEB_BUILD_OPTIONS="debug nostrip noopt" fakeroot apt-get source -b <package>
- Install the needed .debs (they will be in the current working directory if the build succeeded):
sudo debi <package>*.changes
* Most packages support the build of debugging version in this way. If this process doesn't work for a package, please open a bug against it.
The Xorg server
The X server will by default trap its own crashes and dump a stack trace in /var/log/Xorg.0.log. However, this stack trace is modified by the signal handler itself. To get a "normal" crash, which will trigger a core dump (and apport reporting), add this to your /etc/X11/xorg.conf:
Section "ServerFlags"
Option "NoTrapSignals" "true"
EndSectionPlease see DebuggingXorg for how to debug Xorg server crashes.
Info for the BugSquad
If you're trying to apport-retrace a crash report from a bug that didn't happen on the same Ubuntu release as the one you're running, do the following:
Say that you're running feisty and the crash happened on edgy:
This will create a minimal edgy system.
sudo mkdir -p /chroots/edgy sudo debootstrap edgy /chroots/edgy/
Now you change into this minimal edgy system.
sudo chroot /chroot/edgy
edit /etc/apt/sources/list and all the repositories you need, especially Martin's ddeb repository.
apt-get update; apt-get install gdb apport
use apport-retrace as you're used to.